The present invention relates to a boot assembling apparatus for use in a process for assembling a shaft such as a driving shaft for a vehicle by attaching thereto a joint unit such as a constant velocity joint, and more particularly, to an apparatus for assembling a boot for a joint unit or the like to the shaft, the boot having a bead at its leading end adapted to be fitted over the shaft.
An assembling apparatus for the above function has conventionally been known from Japanese Patent Application Laid-open No. 246432/87. An assembling jig is positioned coaxially with the shaft and has a jig body movable toward and away from the shaft in an axial direction of the shaft. A seat is mounted on a leading end of the jig body for receiving an inner end face of the bead of the boot, and a plurality of radially openable and closable claw pieces are mounted on an inner periphery of the seat as to be projectable forwardly of the seat. In this apparatus, the boot is set on the assembling jig so that the claw pieces may be inserted into the bead of the boot while remaining closed and held projecting forwardly of the seat. Then, the claw pieces are opened to clamp the bead and diametrically expand it. In this condition, the jig body is advanced toward the shaft to have an end of the shaft inserted between the claw pieces. The claw pieces are then sunk into the seat when the jig body has been advanced to a given position. This sinking operation results in withdrawal of the claw pieces from the bead seated on the seat, thus having the bead fitted over a predetermined portion of the shaft.
The foregoing apparatus is structurally rather complicated, in that a mechanism for opening and closing the claw pieces is required to be incorporated in the assembling jig. Therefore, it is being considered that in place of the claw pieces, a guide sleeve which can be fitted over the shaft may be mounted on the jig body and projectable forwardly of the seat, so that, for setting a boot on the assembling jig, the bead held in a diametrically expanded state can be fitted over the guide sleeve projecting from the seat.
In the apparatus described in the above publication, a cylinder is provided on the jig body for projecting and retracting the claw pieces, apart from a drive source for reciprocating the jig body. In such an apparatus equipped with the cylinder for providing the projection and retraction of the claw pieces, even if the claw pieces were replaced by the guide sleeve as described above, the assembling jig would still be structurally complicated and large-sized. Therefore, it is desired that the drive source for projecting and retracting the guide sleeve be integrally incorporated in the drive source for reciprocating the jig body to provide a reduction in size and a simplification of the assembling jig. Therefore, it is a first object of the present invention to solve the foregoing problem.
In addition, if the assembling jig and the shaft are out of center alignment with each other, the guide sleeve interferes with the shaft when the jig body is advanced, consequently making it impossible to assemble the boot to the shaft. Therefore, it is a second object of the present invention to remove such inconvenience.
Further, in the above mechanism, the jig body is advanced to a predetermined position to fit the bead of the boot over the shaft and hence, if the shaft is out of the axially aligned position, the bead cannot be fitted over the predetermined portion of the shaft. Accordingly, it is a third object of the present invention to solve such problems.